Self-supporting screens for stone, ore and like material

ABSTRACT

A self-supporting screen for sorting stone, ore and like material having apertures of adjustable size. Two crossed sets of bars are detachably clamped together to form screen lattice. The rods are coated with a wear-resistant natural or synthetic rubber, and at least the bars in one rod set are reinforced to impart self-supporting ability to the screen. The bar sets have cooperating ridges and toothlike projections to fix the positions of the bars in the two bar sets in relation to each other. One bar set may then be displaced with respect to the other bar set utilizing the cooperating ridges and projections to provide a screen having apertures of adjustable size.

United States Patent [72] Inventor Bengt Lars Arne Dehlen Trelleborg, Sweden [21] Appl. No. 806,242 [22] Filed Mar. 11, 1969 [45] Patented Sept. 28, 1971 [73] Assignee Trelleborgs Gummifabriks Aktiebolag [32] Priority Mar. 14, 1968 [33] Sweden 3351/68 [54] SELF-SUPPORTING SCREENS FOR STONE, ORE

AND LIKE MATERIAL 4 Claims, 4 Drawing Figs.

[52] 0.8. Cl 209/394 [51] Int. Cl 1 B07b 1/04 [50] Field of Search 209/392,

[56] References Cited UNITED STATES PATENTS 7 2,837,210 6/1958 Ackert et al. 209/392 X 3,134,733 5/1964 Rose 209/393 3,229,919 1/1966 Hanse m1. 209/394x ronsrou PATENTS 269,877 4/1928 GreatBritain 209/402 Primary Examiner-Frank W. Lutter Assistant Examiner-William Cuchlinski, Jr. Attorney- Beveridge & De Grandi ABSTRACT: A self-supporting screen for sorting stone, ore and like material having apertures of adjustable size. Two crossed sets of bars are detachably clamped together to form screen lattice. The rods are coated with a wear-resistant natural or synthetic rubber, and at least the bars in one rod set are reinforced to impart self-supporting ability to the screen. The bar sets have cooperating ridges and toothlike projections to fix the positions of the bars in the two bar sets in relation to each other. One bar set may then be displaced with respect to the other bar set utilizing the cooperating ridges and projections to provide a screen having apertures of adjustable size.

zlew/ PATENTED SEP28 1971 3 6 08.719

SHEET 3 OF 3 Z I I NV NTQ'! Bauer 1. 10.!

Q SIRVQMQ- Arloklvi Y8 SELF-SUPPORTING SCREENS FOR STONE. ORE AND LIKE MATERIAL In the stone and mining industries there is an ample demand for screens for sorting stones and ores because the screens are subject to heavy wear by the material being screened. For an increased resistance to wear one has begun to use screens which consist of or are provided with a coat of some particularly wear-resistant natural or synthetic rubber. Although the life of the screens has been increased considerably after the introduction of wear-resistant rubber, the previously known screens suffer from a number of drawbacks. When screening such a wearing material as stones and ores, the centrally located areas of the screen in most cases are thus much more rapidly worn than the peripheral areas. To allow exchange of certain parts of the screen the latter has been formed with exchangeable sections. One drawback of these previously known screens is that one is bound to the predetermined dimensions of the screen sections and of the screen holes, and another drawback is that a supporting structure is necessary for supporting the individual sections of the screen.

The present invention has for its purpose to provide a screen for stone, ore and like material, which is self-supporting and permits varying the dimensions of the screen apertures without necessitating exchange of any part of the screen, and which also allows a far-reaching standardization of the individual elements of the screen, without it being necessary to waive the possibilities of varying the construction of the screen in accordance with particular desired service conditions and without being tied to the originally selected particular dimensioning of the screen and the screen apertures. This and other objects are attained according to the invention by composing the screen of bars whose surfaces contacting the material to be screened are made of wear-resistant natural or synthetic rubber. Characteristics of the screen is that it comprises two crossed sets of bars, the bars of at least one set being provided with a reinforcement imparting self-supporting ability to the screen, the bars of said crossed sets having interengaging projections serving to fix the positions of the crossed bars in relation to each other and being forcelockingly interconnected under formation of a screen lattice.

The invention will now be described in greater detail with reference to the accompanying drawings illustrating an embodiment of the screen.

ln the drawings:

HO. 1 is a top plan view of part of the screen and the screen frame;

F 10. 2 is a section on line llll in FIG. 1;

H6. 3 is a section on line Ill-III in FIG. 1;

FIG. 4 is a bottom plan view of part of a rod in said screen.

The screen illustrated in the drawings comprises two crossed sets of bars 11, 12 and 13, 14. In the embodiment shown, the bars 11, 12 of one set are arranged in pairs opposite each other on either side of the rods 13, 14 of the other set. The bars 11 are a composite of a C-shaped elongated, reinforced cavity 15, having interior abutment surfaces 16, and a wear-resistant rubber coating 17 which surrounds the outside surfaces of elongated cavity 15. Additionally, the bars 11 are provided at their downwardly directed-side with projections or teeth 18 which are integral with the other parts of the wear-resistant rubber layer 17. By reason of this design the bars 11 will be in the form of racks. The rods 12 also belonging to the bars of the first set are made from two angle bars 19, which are interconnected by means of wear resistant rubber 21. The composite bar 12 thus consists of an elongated C- shaped cavity made of angle brackets 19 and 20 and a rubber coating 21. disposed on and holding together the cavity. As will appear from FIGS. 2 and 3 this wear-resistant rubber on the outer side of the angle rods (i.e. the upper side of the rods 12) is formed with projections orteeth 22. Besides the wearresistant rubber 21 has elongated through holes 23, and a recess is provided in the wear-resistant rubber around each of said holes so that the angle rods 19, 20 will have free surface portions 24 serving as abutment surfaces.

In the embodiment shown the crossing bars 13 are formed from wear-resistant rubber without any reinforcement, but these bars also may be reinforced. The crossing bars 13 have longitudinal ridges 25 into which the toothlike projections 18, 22 of the bars 11 and 12 fit. The spacing of the ridges 25 is selected in accordance with the division between the toothlike projections 18, 22 of the bars 11 and 12.

The crossing bars 14 have a reinforcement 26 which serves the purpose of rigidifying the screen and imparting self-supporting ability to it. As a rule, the bars 14 are provided only at the ends of the bars ll, 12, but if necessary bars 14 may also be placed at one or more other locations along the length of the bars 11, 12. The bars 14 also have longitudinal ridges 25 the spacing of which has been selected in accordance with the division of the toothlike projections 18, 22 of the bars 11 and 12.

The bars 11-14 are interconnected to form a screen lattice with the aid of bolts 27 which have been passed into the reinforcing profile member 15 and extend downwards between the bars l3, l4 and through the holes 23 in the lower bars 12. The bolts and their nuts thus tighten together the pairwise arranged bars 1 1, l2, clamping the bars 13, 14 between the rods 11, 12. The division of the bolts as well as the number thereof is dependent upon the service conditions of the screen and can therefore be varied at will.

Owing to the racklike design of the bars 11, 12 the size of the screen apertures in the screen can be selected according to a modulus system in which the modulus corresponds to the tooth division which may he say 10 mms. As the parts of the screen are tightened together and permit being tightened together in optionalpositions in accordance with the modulus system, the dimensions of the screen apertures can be changed also after the screen has been put into service, and it is possible to exchange individual rods in the screen in the case of nonuniform wear.

Fastening of the self-supporting screen can be effected in several ways, one suitable way being shown in the drawings. As appears particularly from FIG. 2 the outermost longitudinal bars 12 of the screen rest upon an angle rod 30 secured to the sidewall 31 of the screen frame. The screen rests loosely on the angle rods of the screen frame but is pressed down against said angle rods by means of a rubber profile member 32. Said rubber profile member has a fastening bar 33 vulcanized thereinto for enabling anchoring of the bar by means of bolts 34 in longitudinal holes in the sidewall 31 of the screen frame. in use the screen is thus mounted with the rods 11 and 12 in the screening direction which is designated by an arrow in FIG. 3. The screen according to the present invention may be mounted in a continuous sequence in the screen frame, either in abutting end-to-end application or at successively lower levels in the screening direction. When several individual screens are mounted one after the other it is possible optionally to vary the dimensions of the screen holes within each individual screen, thus making it possible to change the sieve fractions also after the screen has been put into service.

In the illustrated embodiment of the screen the bars 12 have been made more slender than the bars 11 so that the material being screened contacts the bars 12 to the least possible extent. Should itprove necessary, however, the reinforcing elements 19, 20 of the bars 12 can be provided with a layer of wear-resistant rubber also at the outer side.

What 1 claim and desire to secure by Letters Patent is:

l. A screen for sorting stone, ore, and the like material, having apertures which are adjustable in size, comprising:

a plurality of pairs of elongated parallel bars, each parallel bar of said plurality of pairs of parallel bars including an elongated C-shaped cavity,

a plurality of elongated crossing bars situated between respective parallel bars of each pair of said plurality of pairs of parallel bars and crossing said plurality of pairs of parallel bars at an angle of a single aperture of the screen being bounded by an adjacent pair of crossing bars and an adjacent pair of a pair of parallel bars,

detachable clamping means extending between the C- shaped cavities of the respective bars of pairs of said plurality of pairs of parallel bars for clamping the plurality of pairs of parallel bars to the crossing bars,

each of said bars of said plurality of pairs of parallel bars having a plurality of toothlike projections which extend in the direction of said plurality of crossing bars,

each of said crossing bars having two sets of a plurality of ridges, each set extending in the direction of a respective bar of a pair of bars of said plurality of pairs of parallel bars, said ridges being spaced to engage said toothlike projections, whereby the position of said crossing bars may be adjusted relative to the position of said parallel bars and the relative size of the apertures of the screen may be controlled.

2. The screen of claim 1 wherein each parallel bar of said plurality of pairs of elongated parallel bars further includes an elongated coating of a wear-resistant material arranged to coat said C-shaped elongated cavity, and wherein said elongated crossing bars are comprised of a wear-resistant material.

3. The screen of claim 2 wherein said wear-resistant material is chosen from the group consisting of natural rubber and synthetic rubber.

4. The screen of claim 1 wherein said detachable clamping means are bolts having a bolt head at one bolt end and a nut at the other bolt end, said bolt head and nut being shaped to fit into and engage said C-shaped elongated cavities. 

1. A screen for sorting stone, ore, and the like material, having apertures which are adjustable in size, comprising: a plurality of pairs of elongated parallel bars, each parallel bar of said plurality of pairs of parallel bars including an elongated C-shaped cavity, a plurality of elongated crossing bars situated between respective parallel bars of each pair of said plurality of pairs of parallel bars and crossing said plurality of pairs of parallel bars at an angle of 90* , a single aperture of the screen being bounded by an adjacent pair of crossing bars and an adjacent pair of a pair of parallel bars, detachable clamping means extending between the C-shaped cavities of the respective bars of pairs of said plurality of pairs of parallel bars for clamping the plurality of pairs of parallel bars to the crossing bars, each of said bars of said plurality of pairs of parallel bars having a plurality of toothlike projections which extend in the direction of said plurality of crossing bars, each of said crossing bars having two sets of a plurality of ridges, each set extending in the direction of a respective bar of a pair of bars of said plurality of pairs of parallel bars, said ridges being spaced to engage said toothlike projections, whereby the position of said crossing bars may be adjusted relative to the position of said parallel bars and the relative size of the apertures of the screen may be controlled.
 2. The screen of claim 1 wherein each parallel bar of said plurality of pairs of elongated parallel bars further includes an elongated coating of a wear-resistant material arranged to coat said C-shaped elongated cavity, and wherein said elongated crossing bars are comprised of a wear-resistant material.
 3. The screen of claim 2 wherein said wear-resistant material is chosen from the group consisting of natural rubber and synthetic rubber.
 4. The screen of claim 1 wherein said detachable clamping means are bolts having a bolt head at one bolt end and a nut at the other bolt end, said bolt head and nut being shaped to fit into and engage said C-shaped elongated cavities. 